1. Field of the Invention
This invention relates to a new connection link which, being considerably lighter than usual links without loss of strength and hence with a reduced inertial mass in play, is particularly suitable for application to modern high-speed looms.
2. Description of the Prior Art
As is well known, the dobby commands are transmitted to the first crank lever of the control rods of each loom heddle frame by a length-adjustable connection link.
Currently, the impelling requirement in looms, and in particular in air jet looms, for ever increasing operating speed has led to the construction of very lightweight heddle frames with extremely low inertia, however no attempt has yet been made to also lighten the relative connection links which as they undergo almost the same length of travel as the heddle frames have almost the same influence as these latter on the inertia of the system.
In the current state of the art, each length-adjustable connection link is generally in the form of two tubular bars of rectangular cross-section connected axially together by a length-adjustable connection member fixed to the adjacent ends of said tubular bars by spot welds and locked in position by pressure screws.
Said tubular bars are always of steel construction to allow easy and reliable welding of said connection member which, as it necessarily has to be solid and be inevitably inserted a certain distance into both said tubular bars, is also of a not inconsiderable weight, so that the connection link is currently heavy and considerably adds to the inertial forces which the dobby has to overcome.
The object of the present invention is to obviate said drawback by providing a length-adjustable connection link which is extremely light in weight, without this lightness detracting from its strength, the object therefore basically being to provide an aluminum connection link.
However such an aluminum link cannot be constructed in accordance with the known art because of the difficulty in welding the connection member. Again, riveting said member would not ensure a connection of long duration in that rivets inevitably loosen with time and generate slack because of the alternating forces to which the link is subjected; finally, a connection member which could be riveted or brazed, this latter being an extremely costly operation, would still be of excessive weight.